1. Field of the Invention
The present invention relates to an automobile reducer and, more particularly, to an automobile reducer capable of removing of a clearance in the axial direction and a clearance in the direction of rotation, which are generated from a worm shaft bearing and a worm shaft and from the worm shaft and a motor shaft, in the case of a conventional reducer, thereby removing noise and vibration generated from the bearing and the worm shaft, and capable of minimizing the amount of change in clearance, which depends on the change in rotational torque, thereby accurately assisting the driver's steering wheel manipulation.
2. Description of the Prior Art
FIG. 1 is a sectional view of a conventional automobile reducer.
As illustrated in FIG. 1, the conventional automobile reducer 100 is provided with a worm shaft 154, which has a worm 152 formed on the outer peripheral surface thereof, and worm shaft bearings 157a and 157b are installed on both ends of the worm shaft 154, respectively, so as to support the worm shaft 154. In order to prevent the worm shaft bearing 157b from playing in the axial direction of the worm shaft 154, a plug bolt 110 is fastened between a damping coupler 140 and the worm shaft bearing 157b, and the plug bolt 110 is fixed by a plug nut 120.
The worm shaft 154 is connected to a motor shaft 145 of a motor 146 via the damping coupler 140, and the worm shaft 154 is structured to rotate by means of driving of the motor 146.
A worm wheel 156 is provided on one side of the outer diameter of the worm 152, which is formed on the worm shaft 154, so as to mesh with the worm 152, and the worm wheel 156 is structured to be mounted on a steering shaft 106, which transfers a rotating force to a steering wheel (not illustrated) manipulated by the driver, so that the rotating force from the worm shaft 154, which is caused by driving of the motor 146, is transferred to the steering shaft 106.
A gear housing 106 contains the worm shaft 154, the worm wheel 156, and the like. A motor 146 is provided on one side of the gear housing 160 so as to provide the worm shaft 154 with a driving force. The gear housing 160 and the motor 146 are coupled by a motor cover 130 using a bolt 150.
The worm shaft bearing 157b has a ball coupled between inner and outer races, thereby supporting the rotation of the worm shaft 154, which is connected to the motor shaft 145 of the motor 146.
Among the worm shaft bearings 157a and 157b, which support the worm shaft 154, the worm shaft bearing 157b, which supports a part coupled to the motor shaft 145, is provided as a pivot bearing, for example, so that the worm shaft 154 is supported to be able to play.
However, such a conventional automobile reducer has a problem in that, due to the damping coupler, a clearance in the axial direction and a clearance in the direction of rotation are generated from the worm shaft bearing and the worm shaft and from the worm shaft and the motor shaft, and such clearances not only cause the worm shaft bearing and the worm shaft to generate noise and vibration, but also inconvenience the driver.
Furthermore, the worm shaft and the motor shaft cannot rotate simultaneously, due to the clearance in the direction of rotation between the worm shaft and the motor shaft, failing to accurately assist the driver's steering wheel manipulation, and the clearances between the motor and the damping coupler and between the damping coupler and the worm shaft, during the driver's reversed manipulation, cause the worm shaft to jolt.